The `buildArgs` option expects a map of buildArgs representing values for the `--build-arg` flag used for `docker` or `kaniko` build commands.

#### Example: Defining Build Args for Docker
```yaml
images:
  backend:
    image: john/appbackend
    build:
      docker:
        options:
          buildArgs:
            arg1: arg-value-2
            arg2: arg-value-2
```
**Explanation:**  
The image `backend` would be built using `docker` and `docker build` would be called using the `--build-arg arg1=arg-value-1 --build-arg arg2=arg-value-2` flags.
